Impact of pre-operative breast magnetic resonance imaging on contralateral synchronous and metachronous breast cancer detection—A case control comparison study with 1468 primary operable breast cancer patients with mean follow-up of 102 months

BACKGROUND: Women with unilateral breast cancer are at an increased risk for the development of contralateral breast cancers. We hypothesis that combined breast MRI would detect more contralateral synchronous breast cancer than conventional imaging alone, and resulted in less contralateral metachronous breast cancer during follow-up. METHODS: We retrospectively collected two groups of breast cancer patients diagnosed from 2009 to 2013 for evaluating the effectiveness and value of adding pre-operative breast MRI to conventional breast images (mammography and sonography) for detection of contralateral synchronous breast cancer. The new metachronous contralateral breast cancer diagnosed during follow-up was prospectively evaluated and compared. RESULTS: Group A (n = 733) comprised patients who underwent conventional preoperative imaging and group B (n = 735) combined with MRI were enrolled and compared. Seventy (9.5%) of the group B patients were found to have contralateral lesions detected by breast MRI, and 65.7% of these lesions only visible with MRI. The positive predictive value of breast MRI detected contralateral lesions was 48.8%. With the addition of breast MRI to conventional imaging studies, more surgical excisions were performed in contralateral breasts (6% (44/735) versus 1.4% (10/733), P< 0.01), more synchronous contralateral breast cancer detected (2.9% (21/735) versus 1.1% (8/733), P = 0.02), and resulted in numerical less (2.2% (16/714) versus 3% (22/725), p = 0.3) metachronous contralateral breast cancer during a mean follow-up of 102 months. CONCLUSIONS: Our study provides useful estimates of the pre-operative breast MRI for the increased detection of contralateral synchronous breast cancer and less subsequent contralateral metachronous breast cancer.